Fields at Gauss Points

Fields that are computed at each integration point are referenced by codes with the IF prefix (standing for Internal Field).

Metafor Code	Description
`IF_DEV_SIG_XX`	Cauchy stress deviator tensor (see important remark at the bottom)
`IF_DEV_SIG_YY`
`IF_DEV_SIG_ZZ`
`IF_SIG_XX`	Cauchy stress tensor (see important remark at the bottom)
`IF_SIG_YY`
`IF_SIG_ZZ`
`IF_SIG_XY`
`IF_SIG_XZ`
`IF_SIG_YZ`
`IF_SIG_1`	Cauchy Principal stress 1
`IF_SIG_2`	Cauchy Principal stress 2
`IF_SIG_3`	Cauchy Principal stress 3
`IF_DEV_SIG_ORTHO_XX`	Cauchy stress deviator tensor in a frame which moves with the matter (see important remark at the bottom)
`IF_DEV_SIG_ORTHO_YY`
`IF_DEV_SIG_ORTHO_ZZ`
`IF_SIG_ORTHO_XX`	Cauchy stress deviator tensor in a frame which moves with the matter
`IF_SIG_ORTHO_YY`
`IF_SIG_ORTHO_ZZ`
`IF_SIG_ORTHO_XY`
`IF_SIG_ORTHO_XZ`
`IF_SIG_ORTHO_YZ`
`IF_ALP_XX`	“backstress” (kinematic hardening)
`IF_ALP_YY`
`IF_ALP_ZZ`
`IF_ALP_XY`
`IF_ALP_XZ`
`IF_ALP_YZ`
`IF_GL_STRAIN_XX`	Green-Lagrange strains (in the initial frame)
`IF_GL_STRAIN_YY`
`IF_GL_STRAIN_ZZ`
`IF_GL_STRAIN_XY`
`IF_GL_STRAIN_XZ`
`IF_GL_STRAIN_YZ`
`IF_NAT_STRAIN_XX`	Natural strains (in the initial frame)
`IF_NAT_STRAIN_YY`
`IF_NAT_STRAIN_ZZ`
`IF_NAT_STRAIN_XY`
`IF_NAT_STRAIN_XZ`
`IF_NAT_STRAIN_YZ`
`IF_BIOT_STRAIN_XX`	Biot strains (in the initial frame)
`IF_BIOT_STRAIN_YY`
`IF_BIOT_STRAIN_ZZ`
`IF_BIOT_STRAIN_XY`
`IF_BIOT_STRAIN_XZ`
`IF_BIOT_STRAIN_YZ`
`IF_ALP_J2`	contrainte cinématique équivalente
`IF_P`	pressure
`IF_EPL`	equivalent plastic strain
`IF_DEPL`	equivalent plastic strain rate
`IF_EVMS`	von Mises stress
`IF_CRITERION`	Plastic Criterion (different to EVMS if VonMises is not used as plastic Critetion)
`IF_YIELD_STRESS`	yield stress
`IF_VISCOPLAST_STRESS`	Visco-Plastic Stress
`IF_GRAINSIZE`	grain size Value
`IF_GRAINSIZE_STRESS`	grain size Stress
`IF_TRIAX`	stress triaxiality T = hydrostatic stress / equivalent stress
`IF_RUPT_CRIT`	rupture Criterion
`IF_ISO_DAMAGE`	isotropic damage
`IF_DAMAGE_XX`	orthotropic damage
`IF_DAMAGE_YY`
`IF_DAMAGE_ZZ`
`IF_DAMAGE_XY`
`IF_DAMAGE_YZ`
`IF_DAMAGE_XZ`
`IF_RHO`	density
`IF_FLUX_X`	heat flux
`IF_FLUX_Y`
`IF_FLUX_Z`
`IF_GRADT_X`	temperature gradient
`IF_GRADT_Y`
`IF_GRADT_Z`
`IF_DEV_SIG_XX_UPPER_SIDE`	stress deviator tensor - upper skin of a shell
`IF_DEV_SIG_YY_UPPER_SIDE`
`IF_DEV_SIG_ZZ_UPPER_SIDE`
`IF_SIG_XX_UPPER_SIDE`	stress tensor - upper skin of a shell
`IF_SIG_YY_UPPER_SIDE`
`IF_SIG_ZZ_UPPER_SIDE`
`IF_SIG_XY_UPPER_SIDE`
`IF_SIG_XZ_UPPER_SIDE`
`IF_SIG_YZ_UPPER_SIDE`
`IF_P_UPPER_SIDE`	pressure - upper skin of a shell
`IF_EPL_UPPER_SIDE`	equivalent plastic strain - upper skin of a shell
`IF_DEV_SIG_XX_LOWER_SIDE`	stress deviator tensor - lower skin of a shell
`IF_DEV_SIG_YY_LOWER_SIDE`
`IF_DEV_SIG_ZZ_LOWER_SIDE`
`IF_SIG_XX_LOWER_SIDE`	stress tensor - lower skin of a shell
`IF_SIG_YY_LOWER_SIDE`
`IF_SIG_ZZ_LOWER_SIDE`
`IF_SIG_XY_LOWER_SIDE`
`IF_SIG_XZ_LOWER_SIDE`
`IF_SIG_YZ_LOWER_SIDE`
`IF_P_LOWER_SIDE`	pressure - lower skin of a shell
`IF_EPL_LOWER_SIDE`	equivalent plastic strain - lower skin of a shell
`IF_THICKNESS`	deformed thickness of a shell
`IF_CURVATURE_XX`	shell curvatures
`IF_CURVATURE_YY`
`IF_CURVATURE_ZZ`
`IF_CURVATURE_XY`
`IF_CURVATURE_XZ`
`IF_CURVATURE_YZ`
`IF_TORQUE_XX`	shell torques
`IF_TORQUE_YY`
`IF_TORQUE_ZZ`
`IF_TORQUE_XY`
`IF_TORQUE_XZ`
`IF_TORQUE_YZ`
`IF_FTOTAL_XX`	deformation gradient
`IF_FTOTAL_YY`
`IF_FTOTAL_ZZ`
`IF_FTOTAL_XY`
`IF_FTOTAL_XZ`
`IF_FTOTAL_YZ`
`IF_FTOTAL_YX`
`IF_FTOTAL_ZX`
`IF_FTOTAL_ZY`
`IF_LODE_PARAMETER`	Lode parameter $\in [-1,1]$

This codes are to be used in Saving history curves to disk to specify which field must be archived.

Important note: IF_SIG_XX stresses are always Cauchy stresses, whether a hypoelastic or hyperelastic formulation is used. To get Piola-Kirchhoff-2 stresses, the transformation formula must be applied, used the gradient deformation tensor (IF_FTOTAL_XX, …):

$$ \boldsymbol{\sigma}_{\text{cauchy}} = \dfrac{\mathbf{F}\,\boldsymbol{\sigma}_{\text{PK2}}\,\mathbf{F}^T}{\det(\mathbf{F}_{\text{total}})} $$